Abstract Detail

Biochemistry, metabolism, carbon flux

Singer, Stacy Dawn [1], Chen, Guanqun [1], Mietkiewska, Elzbieta [2], Tomasi, Pernell [3], Dyer, John M. [3], Jayawardhane, Kethmi [1], Weselake, Randall J. [1].

A functional characterization of GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE 9 (GPAT9) from the model oilseed plant, Arabidopsis thaliana.

The demand for plant-derived oils has grown considerably over the last few decades, and with our steadily escalating population, it is sure to continue expanding. Although the majority of this oil is used for food applications, there is also an ever-increasing interest in the use of plant oils as a substitute for dwindling petrochemical reserves in the form of renewable feedstocks for the production of biodiesel and industrial chemicals. Unfortunately, our supply of these oils is limited by the availability of arable land, and as a result of this, there has been a surge in research efforts to generate plants with improved oil contents. While many examples of such improvements exist, in most cases the enhancements have only been incremental; results that have been attributed in large part to the complexity of the lipid biosynthetic pathway. Although much progress has been made in recent years to decipher this pathway in plants, there remain gaps in our knowledge concerning the exact roles of several relevant genes. One such gene is GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE (GPAT), which is responsible for the first acylation step in the production of storage oil (triacylglycerol) and remains unidentified in plants. In this presentation, our ongoing functional characterization of AtGPAT9 in the model oilseed species, Arabidopsis thaliana, will be discussed. Using in vitro assay analyses, we found that the AtGPAT9 protein exhibited GPAT activity, preferentially acylating the sn-1 position of the glycerol backbone, and shows a preference for acyl-coenzyme A (CoA) rather than dicarboxylic acid-CoA as its substrate. In addition, over-expression of AtGPAT9 in transgenic plants resulted in significant increases in seed oil content on a per seed basis, while RNAi down-regulation of this gene yielded decreased seed oil. Taken together, our results suggest that AtGPAT9 plays an important role in triacylglycerol biosynthesis in plants.

1 - University of Alberta, Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, Edmonton, AB, T6G 2P5, Canada
2 - University of Alberta, Department of Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, Edmonton, Alberta, T6G 2P5, Canada
3 - US Arid-Land Agricultural Research Center, 21881 North Cardon Lane, Maricopa, AZ, 85138, USA

Keywords:
none specified

Presentation Type: Oral Paper:Papers for Topics
Session: 27
Location: Hall A/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 9:30 AM
Number: 27007
Abstract ID:1090
Candidate for Awards:None